Around the year 915 AD, in autumn, the Danes attacked Porlock. They were at first driven off and Ælfwine's company managed to capture a Danish cnearr at night. At dawn Ælfwine told to his closest friend, Tréowine, he intended to sail off westward, perhaps to the country of the legendary king Sheaf. Tréowine agreed to accompany him at least as far as to Ireland. They got two other companions: Ceola of Somerset and Geraint of West Wales.

Many days after they passed Ireland the voyagers were exhausted. A "dreamlike death" seemed to come over them, and soon they passed out. The last that is known of the journey is that Tréowine saw the world plunge down under them, while sailing the Straight Road.[1]